Sometimes your server may send large amount of outgoing spam (due to compromised email account or scripts) and you may require to clean all emails from Exim mail queue. Following are the few commands that will help you to remove all emails from Exim mail queue using SSH:
To print a list of the messages in the queue:
exim -bp
To remove particular message from the queue:
exim -Mrm {message-id}
To remove all messages from the queue:
exim -bp | awk ‘/^ *[0-9]+[mhd]/{print “exim -Mrm ” $3}’ | bash
OR
exim -bp | exiqgrep -i | xargs exim -Mrm